Vessel sealing instrument

ABSTRACT

A bipolar electrosurgical instrument for clamping, grasping, manipulating, and sealing tissue includes first and second shafts each having a jaw member extending from a distal end thereof and a handle disposed at a proximal end thereof. The handle being operable to effect movement of the jaw members relative to one another from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members cooperate to grasp tissue therebetween. The bipolar instrument is connectable to a source of electrical energy having a first electrical potential connected to one of the jaw members and a second electrical potential connected to the other of the jaw members such that the jaw members are capable of selectively conducting energy though tissue held therebetween to effect a seal. Both the first and second electrical potentials are transmitted to the jaw members through the first shaft.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/474,170, now U.S. Pat. No. 7,582,087, filed Mar. 10, 2004 by PhilipMark Tetzlaff, which claims the benefit of and priority to InternationalApplication No. PCT/US01/11420 filed Apr. 6, 2001, which is acontinuation-in-part of U.S. application Ser. No. 09/425,696 filed Oct.22, 1999 by Philip Mark Tetzlaff et al., now U.S. Pat. No. 6,511,480,which is a continuation-in-part of U.S. application Ser. No. 09/178,027filed Oct. 23, 1998 by Philip Mark Tetzlaff et al., now U.S. Pat. No.6,277,117, the entire contents of each of these applications is herebyincorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to forceps used for open surgicalprocedures. More particularly, the present disclosure relates to aforceps which applies a combination of mechanical clamping pressure andelectrosurgical current to seal tissue.

2. Background of Related Art

A hemostat or forceps is a simple plier-like tool which uses mechanicalaction between its jaws to constrict vessels and is commonly used inopen surgical procedures to grasp, dissect and/or clamp tissue.Electrosurgical forceps utilize both mechanical clamping action andelectrical energy to effect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue.

Certain surgical procedures require scaling and cutting blood vessels orvascular tissue. Several journal articles have disclosed methods forsealing small blood vessels using electrosurgery. An article entitledStudies on Coagulation and the Development of an Automatic ComputerizedBipolar Coagulator, S. Neurosurg., Volume 75, Jul. 1991, describes abipolar coagulator which is used to seal small blood vessels. Thearticle states that it is not possible to safely coagulate arteries witha diameter larger than 2 to 2.5 mm. A second article is entitledAutomatically Controlled Bipolar Electrocoagulation—“COA-COMP”,Neurosurg. Rev. (1984), pp. 187-190, describes a method for terminatingelectrosurgical power to the vessel so that charring of the vessel wallscan be avoided.

By utilizing an electrosurgical forceps, a surgeon can either cauterize,coagulate/desiccate, reduce or slow bleeding and/or seal vessels bycontrolling the intensity, frequency and duration of the electrosurgicalenergy applied to the tissue. Generally, the electrical configuration ofelectrosurgical forceps can be categorized in two classifications: 1)monopolar electrosurgical forceps; and 2) bipolar electrosurgicalforceps.

Monopolar forceps utilize one active electrode associated with theclamping end effector and a remote patient return electrode or pad whichis typically attached externally to the patient. When theelectrosurgical energy is applied, the energy travels from the activeelectrode, to the surgical site, through the patient and to the returnelectrode.

Bipolar electrosurgical forceps utilize two generally opposingelectrodes which are disposed on the inner opposing surfaces of the endeffectors and which are both electrically coupled to an electrosurgicalgenerator. Each electrode is charged to a different electric potential.Since tissue is a conductor of electrical energy, when the effectors areutilized to grasp tissue therebetween, the electrical energy can beselectively transferred through the tissue.

In order to effect a proper seal with larger vessels, two predominantmechanical parameters must be accurately controlled—the pressure appliedto the vessel and the gap between the electrodes both of which affectthickness of the sealed vessel. More particularly, accurate applicationof the pressure is important to oppose the walls of the vessel, toreduce the tissue impedance to a low enough value that allows enoughelectrosurgical energy through the tissue, to overcome the forces ofexpansion during tissue heating and to contribute to the end tissuethickness which is an indication of a good seal. It has been determinedthat a fused vessel wall is optimum between 0.001 and 0.005 inches.Below this range, the seal may shred or tear and above this range thelumens may not be properly or effectively sealed.

With respect to smaller vessel, the pressure applied to the tissue tendsto become less relevant whereas the gap distance between theelectrically conductive surfaces becomes more significant for effectivesealing. In other words, the chances of the two electrically conductivesurfaces touching during activation increases as the vessels becomesmaller.

Electrosurgical methods may be able to seal larger vessels using anappropriate electrosurgical power curve, coupled with an instrumentcapable of applying a large closure force to the vessel walls. It isthought that the process of coagulating small vessels is fundamentallydifferent than electrosurgical vessel sealing. For the purposes herein,“coagulation” is defined as a process of desiccating tissue wherein thetissue cells are ruptured and dried and vessel sealing is defined as theprocess of liquefying the collagen in the tissue so that it reforms intoa fused mass. Thus, coagulation of small vessels is sufficient topermanently close them. Larger vessels need to be sealed to assurepermanent closure.

Numerous bipolar electrosurgical forceps have been proposed in the pastfor various open surgical procedures. However, some of these designs maynot provide uniformly reproducible pressure to the blood vessel and mayresult in an ineffective or non-uniform seal. For example, U.S. Pat. No.2,176,479 to Willis, U.S. Pat. Nos. 4,005,714 and 4,031,898 toHiltebrandt, U.S. Pat. Nos. 5,827,274, 5,290,287 and 5,312,433 to Boebelet al., U.S. Pat. Nos. 4,370,980, 4,552,143, 5,026,370 and 5,116,332 toLottick, U.S. Pat. No. 5,443,463 to Stern et al., U.S. Pat. No.5,484,436 to Eggers et al. and U.S. Pat. No. 5,951,549 to Richardson etal., all relate to electrosurgical instruments for coagulating, cuttingand/or sealing vessels or tissue.

Many of these instruments include blade members or shearing memberswhich simply cut tissue in a mechanical and/or electromechanical mannerand are relatively ineffective for vessel sealing purposes. Otherinstruments rely on clamping pressure alone to procure proper sealingthickness and are not designed to take into account gap tolerancesand/or parallelism and flatness requirements which are parameters which,if properly controlled, can assure a consistent and effective tissueseal. For example, it is known that it is difficult to adequatelycontrol thickness of the resulting sealed tissue by controlling clampingpressure alone for either of two reasons: 1) if too much force isapplied, there is a possibility that the two poles will touch and energywill not be transferred through the tissue resulting in an ineffectiveseal; or 2) if too low a force is applied, a thicker less reliable sealis created.

As mentioned above, in order to properly and effectively seal largervessels, a greater closure force between opposing jaw members isrequired. It is known that a large closure force between the jawstypically requires a large moment about the pivot for each jaw. Thispresents a challenge because the jaw members are typically affixed withpins which are positioned to have a small moment arms with respect tothe pivot of each jaw member. A large force, coupled with a small momentarm, is undesirable because the large forces may shear the pins. As aresult, designers must compensate for these large closure forces byeither designing instruments with metal pins and/or by designinginstruments which at least partially offload these closure forces toreduce the chances of mechanical failure. As can be appreciated, ifmetal pivot pins are employed, the metal pins must be insulated to avoidthe pin acting as an alternate current path between the jaw memberswhich may prove detrimental to effective sealing.

Increasing the closure forces between electrodes may have otherundesirable effects, e.g., it may cause the opposing electrodes to comeinto close contact with one another which may result in a short circuitand a small closure force may cause pre-mature movement of the issueduring compression and prior to activation.

Thus, a need exists to develop a bipolar forceps which effectively sealsvascular tissue and solves the aforementioned problems by providing aninstrument which enables a large closure force between the opposing jawsmembers, reduces the chances of short circuiting the opposing jawsduring activation and assists in manipulating, gripping and holding thetissue prior to and during activation.

SUMMARY

The present disclosure relates to a bipolar electrosurgical instrumentfor use in open surgery which includes first and second shafts one ofwhich is connectable to a source of electrosurgical energy. Each shaftincludes a jaw member extending from a distal end thereof and a handledisposed at a proximal end thereof for effecting movement of the jawmembers relative to one another from a first, open position wherein thejaw members are disposed in spaced relation relative to one another to asecond, closed position wherein the jaw members cooperate to grasptissue therebetween. The source of electrical energy effects first andsecond electrical potentials in the respective jaw members such that thejaw members are capable of selectively conducting energy through tissueheld therebetween to effect a seal.

Preferably, the first and second electrical potentials are created atthe jaw members through the first shaft. For example, in one embodiment,the first electrical potential is transmitted through the first shaft bya lead having a terminal end which electrically interfaces with a distalconnector which connects a first jaw member to the first electricalpotential. The second electrical potential is transmitted through thefirst shaft by a tube disposed within the first shaft which connects thesecond jaw member to the second electrical potential.

The first and second jaw members are connected about a pivot pin. Thedistal connector is preferably interposed between the jaw members andincludes a series of flanges which are dimensioned to prevent theemanation of stray currents from the electrically conductive sealingsurfaces of the jaw members during activation.

Preferably, the distal connector includes a spring washer or wave washerwhich acts as an electrical intermediary between the terminal end andthe jaw member. In one embodiment, the spring washer is beveled toenhance the electrical interface between the terminal end and the jawmember, i.e., beveling causes the spring washer to rotate relative theterminal end during movement of the jaw members from the first to secondpositions which provides a self-cleaning, enhanced running electricalcontact between the terminal end and the jaw member.

Preferably, the distal connector is made from an insulative substrateand is disposed between the jaw members for electrically isolating thefirst and second potentials. In one embodiment, the distal connectorincludes a first surface having at least one recess defined thereinwhich is dimensioned to receive at least a portion of the terminal endof the lead.

In yet another embodiment, one of the jaw members includes a skirt whichis dimensioned to prevent exposure of the terminal end during all anglesof operation, i.e., when the jaw members are disposed in the firstposition, the second position and/or during operative movementtherebetween.

The lead preferably includes a inner core made from a solid ormulti-strand electrically conductive material, e.g., copper/aluminumwire, which is surrounded by an insulative, non-conductive coating,e.g., plastic. In one embodiment, the terminal or distal end of theelectrically conductive material is flattened, i.e., “flat-formed”, andis dimensioned to substantially encircle a boss which extends from thesurface of the distal connector. Preferably, the boss is designed toelectrically insulate the terminal end of the lead from the pivot pin.

In another embodiment, at least one non-conductive stop member isdisposed on an electrically conductive sealing surface of one of the jawmembers. The stop members are designed to control/regulate the distance,i.e., gap, between the jaw members when tissue is held therebetweenduring activation.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1 is a left, perspective view of a forceps according to the presentdisclosure;

FIG. 2 is an enlarged, perspective view of an end effector assembly ofthe forceps of FIG. 1 shown in open configuration;

FIG. 3 is an enlarged, perspective view of the end effector assembly ofthe forceps of FIG. 1 shown in closed configuration;

FIG. 4A is an exploded view of the forceps according to the presentdisclosure;

FIG. 4B is an enlarged, exploded view of the end effector assembly ofFIG. 4A showing the electrical connection of a distal electricalconnector for supplying electrical energy to the end effector assembly;

FIG. 5 is an enlarged, top perspective view of a lower jaw member offorceps with the distal connector seated thereon;

FIG. 6 is a right, perspective view of the forceps of FIG. 1 showngrasping a tissue structure.

FIG. 7 is a enlarged view of the indicated area of detail in FIG. 4Ashowing a proximal electrical interface/connector for supplyingelectrical energy to the end effector assembly; and

FIG. 8 is a cross section of the forceps of FIG. 6 showing theelectrical feed path of a first lead having a first electrical potentialand showing the electrical connection of the proximal electricalinterface of FIG. 7 with a second lead having a second electricalpotential.

DETAILED DESCRIPTION

Referring now to FIGS. 1-4, a forceps 10 for use with open surgicalprocedures includes elongated shaft portions 12 a and 12 b each having aproximal end 16 a and 16 b, respectively, and a distal end 14 a and 14b, respectively. In the drawings and in the descriptions which follow,the term “proximal”, as is traditional, will refer to the end of theforceps 10 which is closer to the user, while the term “distal” willrefer to the end which is further from the user.

The forceps 10 includes an end effector assembly 100 which attaches todistal ends 14 a and 14 b of shafts 12 a and 12 b, respectively. Asexplained in more detail below, the end effector assembly 100 includespair of opposing jaw members 110 and 120 which are pivotably connectedabout a pivot pin 150.

Preferably, each shaft 12 a and 12 b includes a handle 17 a and 17 bdisposed at the proximal end 16 a and 16 b thereof which each define afinger hole 18 a and 18 b, respectively, therethrough for receiving afinger of the user. As can be appreciated, finger holes 18 a and 18 bfacilitate movement of the shafts 12 a and 12 b relative to one anotherwhich, in turn, pivot the jaw members 110 and 120 from an open position(FIG. 2) wherein the jaw members 110 and 120 are disposed in spacedrelation relative to one another to a clamping or closed position (FIG.3) wherein the jaw members 110 and 120 cooperate to grasp tissue 400(FIG. 6) therebetween.

A ratchet 30 is preferably included for selectively locking the jawmembers 110 and 120 relative to one another at various positions duringpivoting. As best shown in FIG. 6, a first ratchet interface, e.g., 30a, extends from the proximal end 16 a of shaft member 12 a towards asecond ratchet interface 30 b in a generally vertically aligned mannersuch that the inner facing surfaces of each ratchet 30 a and 30 b abutone another upon closure about the tissue 400. Preferably, each ratchetinterface 30 a and 30 b includes a plurality of flanges 32 a and 32 b,respectively, which projects from the inner facing surface of eachratchet interface 30 a and 30 b such that the ratchet interfaces 30 aand 30 b interlock in at least one position. In the embodiment shown inFIG. 6, the ratchet interfaces 30 a and 30 b interlock at severaldifferent positions.

Preferably, each position associated with the cooperating ratchetinterfaces 30 a and 30 b holds a specific, i.e., constant, strain energyin the shaft members 12 a and 12 b which, in turn, transmits a specificclosing force to the jaw members 110 and 120. It is envisioned that theratchet 30 may include graduations or other visual markings which enablethe user to easily and quickly ascertain and control the amount ofclosure force desired between the jaw members. A design without aratchet system or similar system would require the user to hold the jawmembers 110 and 120 together by applying constant force to the handles17 a and 17 b which may yield inconsistent results.

As best illustrated in FIG. 1, one of the shafts, e.g., 12 b, includes aproximal shaft connector 19 which is designed to connect the forceps 10to a source of electrosurgical energy such as an electrosurgicalgenerator (not shown). More particularly, proximal shaft connector 19 isformed by a cover 19 a and a flange 19 b which extends proximally fromshaft 12 b. Preferably, cover 19 a and flange 19 b mechanicallycooperate to secure an electrosurgical cable 210 to the forceps 10 suchthat the user may selectively apply electrosurgical energy as needed,

The proximal end of the cable 210 includes a plug 200 having a pair ofprongs 202 a and 202 b which are dimensioned to electrically andmechanically engage the electrosurgical energy generator. As explainedin more detail below with respect to FIG. 8, the distal end of the cable210 is secured to the proximal shaft connector 19 of shaft 12 b by aplurality of finger-like clamping members 77 a and 77 b and a cablecrimp having opposing fingers 76 a and 76 b. The interior of cable 210houses a pair of leads 210 a and 210 b which conduct the differentelectrical potentials from the electrosurgical generator to the jawmembers 110 and 120 as explained in greater detail below.

As best seen in FIGS. 2-4B, the two opposing jaw members 110 and 120 ofthe end effector assembly 100 are pivotable about pin 150 from the openposition to the closed position for grasping tissue 400 therebetween.Jaw members 110 and 120 are generally symmetrical and include similarcomponent features which cooperate to permit facile rotation about pivotpin 150 to effect the grasping and sealing of tissue 400. As a resultand unless otherwise noted, jaw member 110 and the operative featuresassociated therewith will initially be described herein in detail andthe similar component features with respect to jaw member 120 will bebriefly summarized thereafter.

Jaw member 110 includes an insulated outer housing 114 which isdimensioned to mechanically engage an electrically conductive sealingsurface 112 and a proximally extending flange 130 which is dimensionedto seat a distal connector 300 which is described in more detail belowwith respect to FIGS. 4A, 4B and 5. Preferably, outer insulative housing114 extends along the entire length of jaw member 110 to reducealternate or stray current paths during sealing and/or incidentalburning of tissue 400. The inner facing surface of flange 130 includesan electrically conductive plate 134 (FIG. 4B) which conductselectrosurgical energy to the electrically conductive sealing surface112 upon activation.

Likewise, jaw member 120 include similar elements which include: anouter housing 124 which engages an electrically conductive sealingsurface 122; a proximally extending flange 140 which seats the oppositeface of the distal connector 300; an electrically conductive plate 144which conducts electrosurgical energy to the electrically conductivesealing surface 122 upon activation.

It is envisioned that one of the jaw members, e.g., 110, includes atleast one stop member 150 disposed on the inner facing surface of theelectrically conductive sealing surface 112 (and/or 122). The stopmember(s) is preferably designed to facilitate gripping and manipulationof tissue 400 and to define a gap “G” (FIG. 6) between opposing jawmembers 110 and 120 during sealing. A detailed discussion of these andother envisioned stop members 150 as well as various manufacturing andassembling processes for attaching, disposing, depositing and/oraffixing the stop members 150 to the electrically conductive sealingsurfaces 112, 122 are described in commonly-assigned, co-pending U.S.application Ser. No. 12/348,748 entitled “BIPOLAR ELECTRO SURGICALFORCEPS WITH NON-CONDUCTIVE STOP MEMBERS” which is hereby incorporatedby reference in its entirety herein.

FIG. 4A shows an exploded view of the various components of the forceps10 and the inter-operative relationships among the same. Moreparticularly and in addition to the components described above withrespect to FIGS. 1-3 above, shaft 12 a is preferably hollow to define alongitudinal channel 15 a disposed therethrough which is dimensioned toreceive a tube 60 a therein. Tube 60 a includes a proximal end 64 a, adistal end 62 a and at least one mechanical interface 61 a disposedtherebetween. Shaft 12 a also includes a cover plate 50 which isdesigned for snap-fit engagement within an aperture/cavity 45 a definedthrough the outer surface of shaft 12 a. Cover plate 50 includes aseries of opposing flanges 51 a and 51 b which extend therefrom whichare dimensioned to secure the tube 60 a within shaft 12 a as describedbelow. A second flange 52 secures the cover plate 50 to the shaft 12 a.

During assembly, the proximal end 64 a of tube 60 a is slideableincorporated within channel 15 a such that mechanical interface 61 a ispoised for engagement with cover plate 50. Cover plate 50 is thensnapped into cavity 45 a such that flanges 51 a and 51 b secure tube 60a within shaft 12 a. It is envisioned that the cavity 45 a of shaft 12 amay include at least one detent (not shown) which engages mechanicalinterface 61 a disposed along the outer surface of tube 60 a tolimit/prevent rotation of the tube 60 a relative to the shaft 12 a. Thiscooperative relationship is shown by way of example with respect todetents 75 a and 75 b and interfaces (e.g., notches) 61 b of shaft 12 bin FIG. 8. In this instance, flanges 51 a and 51 b (much like flanges 42a and 42 b of cover plate 40 in FIG. 8) hold the detents 75 a and 75 bin FIG. 8) in secure engagement within the notch(es) 61 a to preventrotational and/or longitudinal movement of the tube 60 a within thechannel 15 a.

Preferably, the proximal-most end of tube 60 a includes a slit-likeinterface 65 a which mechanically engages a corresponding tongue 88 aextending from the inner surface of shaft 12 a within cavity 45 a. It isenvisioned that tongue 88 a also prevents rotational movement of thetube 60 a within the shaft 12 a. Alternatively, slit 65 a may be formedto allow radial contraction and expansion of the tube 60 a to promotefriction-fit engagement between the tube 60 a and the shaft 12 a. Otherinterfaces are also envisioned which will facilitate engagement of theshaft 12 a and the tube 60 a, e.g., snap-fit, spring-lock, locking tabs,screw-like interface, tongue and groove, etc.

The distal end 62 a of tube 60 a is preferably dimensioned to engage jawmember 120, i.e, the distal end 62 a includes a slit-like interface 66 awhich promotes simple, secure friction-fit engagement of the tube 60 awith the jaw member 120. More particularly and as mentioned above, jawmember 120 includes a proximally extending flange 130 having a sleeve128 extending proximally therefrom which is dimensioned such that, uponinsertion of the sleeve 128 within distal end 62 a, slit-like interface66 a expands radially outwardly and securely locks the jaw member 120 totube 60 a. Again, other methods of attachment are also envisioned whichwould serve the same purpose, e.g., snap-locks, locking tabs,spring-locks, screw-like interface, tongue and groove, etc.

As can be appreciated by the present disclosure, the arrangement ofshaft 12 b is slightly different from shaft 12 a as shown best in FIGS.4B, 7 and 8. More particularly, shaft 12 b is also hollow to define achannel 15 b therethrough and is dimensioned to receive a tube 60 btherein. Tube 60 b includes a proximal end 64 b and a distal end 62 bwhich attach in a generally similar fashion as their counterpartcomponents with respect to shaft 12 a. For example, the proximal end 64b of tube 60 b is slideable incorporated within channel 15 b such that amechanical interface 61 b disposed on the outer surface of tube 60 b ispoised for engagement with a cover plate 40 (FIGS. 4A and 8).

Preferably and since the forceps 10 is uniquely designed to incorporateall of the electrical interfaces and connections within and along asingle shaft, e.g., 12 b, shaft 12 b includes a slightly larger cavity45 b defined therein for housing and securing the various electricalconnections associated with the forceps 10 as described below. Forexample, cover plate 40 is dimensioned slightly differently than coverplate 50 mostly due to the spatial considerations which must be takeninto account for incorporation of the various internally disposedelectrical connections. However, cover plate 40 does snap atop shaft 12b such that a pair of flanges 42 a and 42 b secure tube 60 b withinshaft 12 b in a similar manner as described above. For example, FIG. 8shows a pair of detents 75 a and 75 b disposed within the cavity 45 b ofshaft 12 b which engage a corresponding number of mechanical interfaces61 b disposed along the outer surface of tube 60 b to limit/preventrotation of the tube 60 b relative to the shaft 12 b. When assembled,each flange 42 a and 42 b is pushed into a corresponding groove 73 a and73 b, respectively, which effectively maintain/hold the detents 75 a and75 b in secure engagement within the notches 61 b to prevent rotationaland/or longitudinal movement of the tube 60 b within the channel 15 b.

End 64 b of tube 60 b also includes a slit-like interface 65 b whichmechanically engages a corresponding tongue 88 b extending from theinner surface of shaft 12 b within cavity 45 b. It is envisioned thattongue 88 a also prevents rotational movement of the tube 60 b withinthe shaft 12 b. Alternatively, slit 65 b may be formed to allow radialcontraction and expansion of the tube 60 b to promote friction-fitengagement between the tube 60 b and the shaft 12 b.

Unlike tube 60 a, tube 60 b is designed as an electrical conduit fortransmitting electrosurgical energy to jaw member 110 which is explainedin more detail below with respect to FIGS. 7 and 8. The distal end 62 bof tube 60 b is preferably dimensioned to engage jaw member 110, i.e.,the distal end 62 b includes a slit-like interface 66 b which promotessimple, secure friction-fit engagement of the tube 60 b with the jawmember 110. This is best illustrated in FIG. 4B which shows proximallyextending flange 130 of jaw member 110 having a terminal sleeve 138which extends therefrom. Terminal sleeve 138 is dimensioned such that,upon insertion of the terminal sleeve 138 within distal end 62 b,slit-like interface 66 b expands radially outwardly and securely locksthe jaw member 110 to tube 60 b.

As can be appreciated, terminal end 138 is at least partially made froman electrically conductive material such that an electrosurgicalpotential is effectively conducted from the tube 60 b, through theterminal sleeve 138, across plate 134 and to the electrically conductivesealing plate 112 upon activation. As mentioned above, the outerinsulative housing 114 of jaw member 110 effectively eliminates strayelectrical currents and incidental burning of tissue across the intendedelectrical path.

As best shown in FIG. 4B, jaw member 110 includes a raceway 135extending proximally from the flange 130 which includes terminal sleeve138 a t the proximal-most end thereof. The terminal sleeve 138 connectsto the conductive tube 60 b disposed within shaft 12 b as describedabove. Raceway 135 serves two purposes: 1) to provide electricalcontinuity from the terminal sleeve 138, through the electricallyconductive plate 134 and to the electrically conductive sealing surface112; and 2) to provide a channel for guiding lead 210 a to the distalconnector 300 as described below.

Insulated outer housing 114 is dimensioned to securely engage theelectrically conductive sealing surface 112. It is envisioned that thismay be accomplished by stamping, by overmolding, by overmolding astamped electrically conductive sealing plate and/or by overmolding ametal injection molded seal plate. All of these manufacturing techniquesproduce an electrode having an electrically conductive surface 112 whichis substantially surrounded by an insulated outer housing 114.

It is envisioned that the jaw member may also include a second insulator(not shown) disposed between the electrically conductive sealing surface112 and the outer insulative housing 114. The insulated outer housing114 and the electrically conductive sealing surface 112 (and the otherinsulator if utilized) are preferably dimensioned to limit and/or reducemany of the known undesirable effects related to tissue sealing, e.g.,flashover, thermal spread and stray current dissipation.

It is also envisioned that the electrically conductive sealing surface112 may include a pinch trim (not shown) which facilitates secureengagement of the electrically conductive surface 112 to the insulatedouter housing 114 and also simplifies the overall manufacturing process.It is also contemplated that the electrically conductive sealing surface112 may include an outer peripheral edge which has a radius and theinsulated outer housing 114 meets the electrically conductive sealingsurface 112 along an adjoining edge which is generally tangential to theradius and/or meets along the radius. Preferably, at the interface, theelectrically conductive surface 112 is raised relative to the insulatedouter housing 114. These and other envisioned embodiments are discussedin concurrently-filed, co-pending, commonly assigned Application Ser.No. 10/474,168 entitled “ELECTROSURGICAL INSTRUMENT WHICH REDUCESCOLLATERAL DAMAGE TO ADJACENT TISSUE” by Johnson et al. andconcurrently-filed, co-pending, commonly assigned Application Ser. No.10/474,226 entitled “ELECTROSURGICAL INSTRUMENT WHICH IS DESIGNED TOREDUCE THE INCIDENCE OF FLASHOVER” by Johnson et al.

As best illustrated in the exploded view of FIG. 4B, the inner peripheryof tube 60 b is preferably dimensioned to house lead 210 a therethroughsuch that a different electrically potential can be effectivelytransmitted to jaw member 120. More particularly and as mentioned above,cable 210 houses two leads 210 a and 210 b having different electricalpotentials. The first lead 210 a is disposed through tube 60 b andconducts the first electrical potential to jaw member 120 as describedin more detail below. The second lead 210 b is electrically interfacedwith tube 60 b at a proximal connector 80 (FIG. 7) which includes aseries of electrical crimps 85, 87 and 89 for securing lead 210 b totube 60 b. As a result, tube 60 b carries the second electricalpotential therethrough for ultimate connection to jaw member 110 asdescribed above.

Lead 210 a preferably includes an insulative coating 213 which surroundsan inner core or electrical conductor 211 (e.g., wire) disposed thereinto insulate the electrical conductor 211 from the tube 60 b duringactivation. It is envisioned that the wire 211 may be made from a solidor multi-strand electrically conductive material, e.g., copper/aluminum,which is surrounded by an insulative, non-conductive coating 213, e.g.,plastic.

The wire 211 includes a terminal end 212 which is dimensioned toelectrically interface with jaw member 120. Preferably, the terminal end212 is “flat-formed” in a generally arcuate shape to encircle acorresponding boss 314 which extends upwardly from the distal connector300 towards jaw member 120 as described below. It is envisioned that thedistal connector 300 performs at least two functions: 1) to insulate jawmember 110 from jaw member 120; and 2) to provide a running electricalconnection for lead 210 a to jaw member 120.

More particularly, the distal connector 300 is generally shaped to matchthe overall profile of the electrically conductive face plates 134 and144 of jaw members 110 and 120, respectively, such that, upon assembly,outer facing surfaces 302 and 304 of the distal connector 300 abutagainst the corresponding plates 134 and 144 of jaw member 110 and 120,respectively. It is envisioned that the outer facing surface 302 of thedistal connector 300 acts as a runway surface which facilitatespivotable motion of jaw member 120 about pivot pin 151 relative to jawmember 110. Preferably, the distal connector 300 is made form aninsulative substrate such as plastic or some other non-conductivematerial.

The distal connector includes a series of flanges 322 and 326 whichextend towards jaw member 120 and a second series of flanges 324 and 328which extend towards jaw member 110. It is envisioned that these flanges322, 324, 326 and 328 insulate the other operative components of theforceps 10 and the patient from stray electrical currents emanating fromthe electrically conductive plates 134 and 144 during activation.Flanges 322 and 328 may also be dimensioned to limit/restrict theexpansion of tissue 400 beyond the sealing surfaces 112 and 122 duringactivation, Flanges 326 and 324 are preferably dimensioned to insulatethe forceps during all angles of operation, i.e., pivoting of the jawmembers 110 and 120.

As mentioned above, the distal connector 300 includes a boss 314 whichextends towards jaw member 120 which is dimensioned to secure theterminal end 212 of lead 210 a. Preferably, the boss is designed toelectrically insulate the terminal end of the lead from the pivot. Theboss 314 preferably defines an aperture 316 therethrough for receivingthe pivot pin 151 and to allow pivotable motion of jaw member 120 aboutthe pivot 151 and the boss 314 relative to jaw member 110.

A continuous series of recesses 312, 318 and 319 are formed around andproximate boss 314 to seat the flat-formed terminal end 212, the wire211 and the insulated portion of the lead 210 a, respectively. This alsosecures lead 210 a to the distal connector and limits movement of thesame (210 a). In some cases it may be preferable to include a dollop ofsilicone or other non-conductive material at the junction between thewire and the terminal end 212 as an added and/or alternative insulatingsafeguard. It is also envisioned that flange 326 may include a notch(not shown) disposed therethrough which facilitates assembly of the lead210 a atop the distal connector 300. As can be appreciated, thiseliminates the step of forming the arcuately-shaped terminal end 212after insertion through channel 318. As mentioned above, a dollop ofsilicone or the like may be added atop/within the notch for insulationpurposes after the terminal end 212 is seated within the distalconnector 300.

The proximal-most portion of distal connector 300 includes a finger 320which is dimensioned to seat within a channel 137 formed within theraceway 135 such that the distal connector 300 moves in connection withjaw member 110 during pivoting. Channel 135 may be formed during amolding process, subsequently bored after the raceway 135 is formed orby any other known method of formation. The uppermost edge of boss 314is preferably dimensioned to seat within a corresponding recess (notshown) formed within plate 144. Likewise and although not shown, it isenvisioned that the opposite end of boss 314 extends towards plate 134and seats within a recess 131 formed within plate 134. It is envisionedthat recess 131 promotes engagement of the distal connector 300 with thejaw member 110.

The distal connector 300 also includes a spring washer or wave washer155 which is preferably dimensioned to encircle the boss 314 atopterminal end 212. Upon assembly, the washer 212 is sandwiched/wedgedbetween the terminal end 212 and the conductive plate 144 of jaw member120. It is envisioned that the washer 155 enhances the connectionbetween the terminal end and the plate 144. More particularly, thewasher 155 is preferably shaped such that the washer 155 provides aself-cleaning, running electrical contact between the terminal end 212and the jaw member 120. It is contemplated that the washer 155“self-cleans” due to the frictional contact and relative movement of thewasher 155 with respect to the terminal end 212 during pivoting of thejaw members 110 and 120. The self-cleaning action can be attributed tothe washer 155 rubbing, scoring and/or digging against the terminal end212 and/or the plate 144 during pivoting of the jaw members 110 and 120.

The outer housing of each of the jaw members 110 and 120 preferablyincludes an additional recess or circular groove 129 which receives aring-like insulator 153 b and 153 a, respectively. Insulators 153 a and153 b insulate the pivot pin 150 from the jaw members 110 and 120 whenthe forceps 10 is assembled. Preferably, the pivot pin 150 is peened tosecure the jaw members 110 and 120 during assembly and may include outerrims 151 a and 151 b at least one of which is peened or formed after thejaw members 110 and 120 are assembled about the pivot pin 150 as bestshown in FIG. 4B.

Upon activation, the first electrical potential is carried by lead 210 athrough tube 60 b to the terminal end 212. The washer 155 of the distalconnector 300 then conducts the first potential to face plate 144 whichcarries the first potential to sealing plate 122 disposed on the innerfacing surface of jaw member 120. The second potential is carried bylead 210 b which electrically interfaces with the tube 60 b (by way ofcrimps 85, 87 and 89) to conduct the second potential to terminal sleeve138 of jaw member 110. The terminal sleeve 138 electrically connects tosealing surface 112 across face plate 134.

FIG. 8 shows the connection of the cable 210 within the cavity 45 b ofshaft 12 b. As mentioned above a series of finger-like elements 77 a and77 b and crimps 76 a and 76 b secure the cable 210 within shaft 12 b.Preferably, cable 210 is secured at an angle alpha (α) relative to alongitudinal axis “A” disposed along shaft 12 b. It is envisioned thatangling the cable 210 in an inward direction, i.e., towards shaft 12 a,facilitates handling of the forceps 10 and the cable 210 during surgery,i.e., the angled disposition of the cable 210 as it exits the forceps 10tends to reduce cable tangling and/or cable interference duringhandling.

Preferably at least one of the jaw members 110 and 120 includes askirt-like feature 126 and 136, respectively, which is dimensioned toprevent exposure of the terminal end 212 or wire 211 during all anglesof operation, i.e., when the jaw members 110 and 120 are disposed in thefirst open position, the second closed position and/or during operativemovement therebetween.

It is envisioned that by making the forceps 10 disposable, the forceps10 is less likely to become damaged since it is only intended for asingle use and, therefore, does not require cleaning or sterilization.As a result, the functionality and consistency of the vital sealingcomponents, e.g., the conductive surfaces 112 and 122, the stopmember(s) 150, and the insulative housings 124 and 114 will assure auniform and quality seal.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the present disclosure For example, it may be preferable to include atang which facilitates manipulation of the forceps 10 during surgery.

Moreover, although the electrical connections are preferablyincorporated with the bottom shaft 12 b and the instrument is intendedfor right-handed use, it is contemplated the electrical connections maybe incorporated with the other shaft 12 a depending upon a particularpurpose and/or to facilitate manipulation by a left-handed user.

It is also contemplate that a shrink tube may be employed over theproximal connector 80 and/or the other various solder or crimpconnections 85, 87 and 89 associated with the proximal connector 80interface with lead wire 210 b. This provides additional insulatingprotection during assembly. It is also contemplated that the forceps 10(and/or the electrosurgical generator used in connection with theforceps 10) may include a sensor or feedback mechanism (not shown) whichautomatically selects the appropriate amount of electrosurgical energyto effectively seal the particularly-sized tissue 400 grasped betweenthe jaw members 110 and 120. The sensor or feedback mechanism may alsomeasure the impedance across the tissue during sealing and provide anindicator (visual and/or audible) that an effective seal has beencreated between the jaw members 110 and 120.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

1. A bipolar electrosurgical instrument for use in open surgery,comprising: first and second shafts each having a jaw member extendingfrom a distal end thereof and a handle disposed at a proximal endthereof for effecting movement of the jaw members relative to oneanother from a first position wherein the jaw members are disposed inspaced relation relative to one another to a second position wherein thejaw members cooperate to grasp tissue therebetween, the first jaw memberbeing adapted to connect to a first electrical potential and the secondjaw member being adapted to connect to a second electrical potentialsuch that the jaw members are capable of selectively conducting energythrough tissue held therebetween to effect a tissue seal; and whereinthe first and second electrical potentials are transmitted to the jawmembers through the first shaft, the first electrical potential beingtransmitted by a lead having a terminal end that interfaces with adistal connector to connect one of the jaw members to the firstelectrical potential, the distal connector including an electricallyconductive spring washer operably disposed between the terminal end andthe jaw member.
 2. A bipolar electrosurgical instrument for use in opensurgery according to claim 1, wherein the second electrical potential istransmitted through the first shaft by a tube disposed within the firstshaft that connects the other of the jaw members to the secondelectrical potential.
 3. A bipolar electrosurgical instrument for use inopen surgery according to claim 2 wherein the lead is fed to the distalconnector through the tube and the lead includes an insulative coatingto insulate the lead from the tube during activation.
 4. A bipolarelectrosurgical instrument for use in open surgery according to claim 1wherein the spring washer is configured to enhance the electricalinterface between the terminal end and the jaw member.
 5. A bipolarelectrosurgical instrument for use in open surgery according to claim 4wherein the spring washer is configured to rotate relative the terminalend during movement of the jaw members from the first to secondpositions to provide a self-cleaning, enhanced electrical contactbetween the terminal end and the jaw member.
 6. A bipolarelectrosurgical instrument for use in open surgery according to claim 1wherein the distal connector is made from an insulative substrate and isinterposed between the jaw members for electrically isolating the firstand second potentials.
 7. A bipolar electrosurgical instrument for usein open surgery according to claim 6 wherein the distal connectorincludes a first surface having at least one recess defined therein thatis configured to receive at least a portion of the terminal end.
 8. Abipolar electrosurgical instrument for use in open surgery according toclaim 7 wherein at least one of the jaw members includes a skirt that isconfigured to prevent exposure of the terminal end when the jaw membersare disposed in the first position, the second position and duringoperative movement therebetween.
 9. A bipolar electrosurgical instrumentfor use in open surgery according to claim 1 wherein the terminal endincludes a flat-formed wire.
 10. A bipolar electrosurgical instrumentfor use in open surgery according to claim 9 wherein the jaw members areconnected by a pivot and the flat-formed wire is configured tosubstantially encircle a boss extending from the distal connector thatis configured to receive the pivot.
 11. A bipolar electrosurgicalinstrument for use in open surgery according to claim 1 wherein the jawmembers are connected by a pivot and the distal connector includes aboss extending therefrom that is configured to electrically insulate theterminal end from the pivot.
 12. A bipolar electrosurgical instrumentfor use in open surgery, comprising: first and second shafts each havinga jaw member pivotable about a pivot pin and extending from a distal endthereof and a handle disposed at a proximal end thereof for effectingmovement of the jaw members relative to one another from a firstposition wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw memberscooperate to grasp tissue therebetween, each of the jaw membersincluding an electrically conductive sealing surface adapted to connectto an electrical energy source wherein a first electrical potential isconnected to one of the jaw members and a second electrical potential isconnected to the other of the jaw members such that the jaw members arecapable of selectively conducting energy through tissue heldtherebetween to effect a tissue seal; the first and second electricalpotentials being transmitted to the jaw members through the first shaftwherein the first electrical potential is transmitted by a lead having aterminal end that electrically interfaces with one of the jaw members;and an electrically conductive spring washer disposed between theterminal end and one of the jaw members, the spring washer movablerelative the terminal end during movement of the jaw members from thefirst to second positions to provide an enhanced electrical contactbetween the terminal end and the jaw member.
 13. A bipolarelectrosurgical instrument for use in open surgery according to claim 12wherein the second electrical potential is transmitted through the firstshaft by a tube disposed within the first shaft that connects the otherjaw member to the second electrical potential.
 14. A bipolarelectrosurgical instrument for use in open surgery according to claim 12further comprising an insulator disposed between the jaw members forelectrically isolating the first and second potentials.
 15. A bipolarelectrosurgical instrument for use in open surgery according to claim 12wherein the terminal end includes a flat-formed wire.
 16. A bipolarelectrosurgical instrument for use in open surgery according to claim 12further comprising at least one non-conductive stop member locateddistally from the pivot pin and operatively associated with at least oneof the jaw members to control the distance between the jaw members whentissue is held therebetween.